1. Field of the Invention
This invention relates to temperature sensors and, more particularly, to a temperature sensor including a semiconductor as the sensing element, the semiconductor utilizing the band edge absorption principle of the semiconductor for sensing temperature by absorbing monochromatic radiant energy at a function of the temperature.
2. The Prior Art
Conventional temperature probes utilizing metallic wires and sensors are unusable in the presence of electromagnetic fields because of the inherent electrical interference problems and field perturbation effects. Accordingly, several non-perturbing temperature probes have been fabricated and are either commercially available or described in the literature. For example, fiberoptic temperature probes have been fabricated and have been reported in the literature. Among these are (1) the liquid crystal temperature probe (see "A Prototype Liquid Crystal Fiberoptic Probe for Temperature and Power Measurements in R. F. Fields", Johnson, C. C., et al, Microwave Journal, volume 18, number 8, pages 55-59, August 1975); (2) the birefringent crystal optical thermometer (see "A Birefringent Crystal Optical Thermometer for Measurements of Electromagnetically Induced Heating", Cetas, T. C., U.S.N.C/U.R.S.I" 1975 annual meeting, Boulder, Colorado, Oct. 20-23, 1975); and (3) the Etalon Fiberoptic Probe (see "Temperature Measurement Using Optical Etalons", Christensen, D. A. 1975 Annual Meeting of the Optical Society of America, Houston, Texas, Oct. 15-18, 1974).
The various non-perturbing temperature probes are useful particularly in the measurement of tissue temperature in the presence of an electromagnetic field. This is particularly important where temperature measurements of tissue are performed simultaneously with irradiation by electromagnetic energy. Such tissue treatments include hyperthermia treatment of cancer, microwave biohazards studies and microwave heating, drying, and cooking. To be useful and widely accepted in the trade, it is desirable that the non-perturbing temperature probe be small in diameter at the tip region (less than 0.5 mm), have a stable calibration for at least several weeks, an accuracy of at least 0.2.degree. C. or better, reasonably simple and inexpensive to use and possess a wide temperature range suitable for various tissue treatment procedures (33.degree. C. to about 47.degree. C.), and, additionally, possess a broader temperature range for microwave heating, drying, and cooking.
Each of the foregoing prior art devices are useful. However, it would be an advancement in the art to provide a non-perturbing temperature probe which meets at least some of the previously listed requirements. Such a temperature probe is disclosed and claimed herein.